scholarly journals Studies on Novel Anti-jamming Technique of Unmanned Aerial Vehicle Data Link

2008 ◽  
Vol 21 (2) ◽  
pp. 141-148 ◽  
Author(s):  
Huang Wenzhun ◽  
Wang Yongsheng ◽  
Ye Xiangyang
2021 ◽  
Vol 13 (6) ◽  
pp. 1134
Author(s):  
Anas El-Alem ◽  
Karem Chokmani ◽  
Aarthi Venkatesan ◽  
Lhissou Rachid ◽  
Hachem Agili ◽  
...  

Optical sensors are increasingly sought to estimate the amount of chlorophyll a (chl_a) in freshwater bodies. Most, whether empirical or semi-empirical, are data-oriented. Two main limitations are often encountered in the development of such models. The availability of data needed for model calibration, validation, and testing and the locality of the model developed—the majority need a re-parameterization from lake to lake. An Unmanned aerial vehicle (UAV) data-based model for chl_a estimation is developed in this work and tested on Sentinel-2 imagery without any re-parametrization. The Ensemble-based system (EBS) algorithm was used to train the model. The leave-one-out cross validation technique was applied to evaluate the EBS, at a local scale, where results were satisfactory (R2 = Nash = 0.94 and RMSE = 5.6 µg chl_a L−1). A blind database (collected over 89 lakes) was used to challenge the EBS’ Sentine-2-derived chl_a estimates at a regional scale. Results were relatively less good, yet satisfactory (R2 = 0.85, RMSE= 2.4 µg chl_a L−1, and Nash = 0.79). However, the EBS has shown some failure to correctly retrieve chl_a concentration in highly turbid waterbodies. This particularity nonetheless does not affect EBS performance, since turbid waters can easily be pre-recognized and masked before the chl_a modeling.


2016 ◽  
Vol 8 (5) ◽  
pp. 416 ◽  
Author(s):  
Shenghui Fang ◽  
Wenchao Tang ◽  
Yi Peng ◽  
Yan Gong ◽  
Can Dai ◽  
...  

Author(s):  
Guo Shichao ◽  
Guo Dandan ◽  
Zhang Qiongyu ◽  
Wu Nankai ◽  
Deng Jiaxin

2017 ◽  
Vol 8 ◽  
Author(s):  
Shane C. Lishawa ◽  
Brendan D. Carson ◽  
Jodi S. Brandt ◽  
Jason M. Tallant ◽  
Nicholas J. Reo ◽  
...  

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3391 ◽  
Author(s):  
Roberto Opromolla ◽  
Giancarmine Fasano ◽  
Domenico Accardo

This paper presents a visual-based approach that allows an Unmanned Aerial Vehicle (UAV) to detect and track a cooperative flying vehicle autonomously using a monocular camera. The algorithms are based on template matching and morphological filtering, thus being able to operate within a wide range of relative distances (i.e., from a few meters up to several tens of meters), while ensuring robustness against variations of illumination conditions, target scale and background. Furthermore, the image processing chain takes full advantage of navigation hints (i.e., relative positioning and own-ship attitude estimates) to improve the computational efficiency and optimize the trade-off between correct detections, false alarms and missed detections. Clearly, the required exchange of information is enabled by the cooperative nature of the formation through a reliable inter-vehicle data-link. Performance assessment is carried out by exploiting flight data collected during an ad hoc experimental campaign. The proposed approach is a key building block of cooperative architectures designed to improve UAV navigation performance either under nominal GNSS coverage or in GNSS-challenging environments.


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